Purpose. Carrier pigs have been considered as the major reservoir of Streptococcus suis and couldbe a significant source of human infection. Therefore, we investigated the prevalence and characteristics of latent S. suis in asymptomatic pigs in the pig-farming area of central Thailand, and compared the data to those previously reported in other regions. Methodology. We collected samples from 340 asymptomatic pigs. S. suis isolates from the samples were confirmed by species-specific PCR (recN PCR). The capsular polysaccharide synthesis gene (cps) types, virulence-associated gene profiles and sequence types (STs) of the isolates were investigated. Results/Key findings. The prevalence of S. suis found in this study was 37 % (125/340 pigs). The most prevalent genotype was mrp −/epf −/sly −. Among the 16 cps-types identified in 135 isolates, cps-type 16 was the most frequent (11 %), whereas 44 % of the isolates were non-typable. In common with the strains causing human sepsis in Thailand, two cps-type 9 isolates and a cps-type 24 isolate from slaughtered pigs belonged to ST16 and ST221, respectively. All the isolated cps-type 2 strains were confirmed as serotype 2 by co-agglutination tests, and these belonged to ST104, the unique ST commonly found in Thai patients; however, in contrast to the endemic areas, the prevalence of serotype 2 strains was relatively low (2 %) and no ST1 isolate was found. Conclusion. Our results showed the population structure differences between S. suis in central Thailand and other regions; however, zoonotic S. suis is certainly latent in asymptomatic pigs in this intensive swine production area.

Background and Aim: According to the previous study, the circulating canine parvovirus (CPV) in Thailand is 2a and 2b. Nowadays, CPV mutants, including CPV-2c, have been identified in many parts of the world. This study aimed to investigate the genetic diversity of the circulating CPV in Thailand. Materials and Methods: Eighty-five CPV-positive fecal samples were obtained from dogs with either acute hemorrhagic diarrhea or diarrhea. The complete VP2 gene of these samples was amplified using VP2 specific primers and polymerase chain reaction (PCR). The obtained full-length VP2 sequences were analyzed and a phylogenetic tree was constructed. Results: Sixty and 25 CPV-positive fecal samples were collected in 2010 and 2018, respectively. Thirty-four samples were new CPV-2a and 31 samples were new CPV-2b due to amino acids substitution at position 297 (Ser-Ala). In 2018, 5 new CPV-2a, 19 CPV-2c, and 1 feline panleukopenia virus (FPV) were found, but no new CPV-2b was detected. Moreover, most of the CPV in this study had amino acids mutations at positions 324 and 440. The phylogenetic construction demonstrated the close relationship between the current new CPV-2a with the previous CPV-2a reported from Thailand, China, Uruguay, Vietnam, Singapore, and India. Interestingly, the current new CPV-2b in this study was not closely related to the previous CPV-2b reported in Thailand. The CPV-2c in this study was closer to Asian CPV-2c and further from either European or South America CPV-2c. Interestingly, FPV was identified in a diarrhea dog. Conclusion: The evolution of CPV in Thailand is very dynamic. Thus, it is important to monitor for CPV mutants and especially the clinical signs relating to these mutants to conduct surveillance for the emergence of new highly pathogenic CPV in the future.

Background and Aim: Streptococcus suis is an important zoonotic pathogen that can cause serious diseases in both swine and humans worldwide, especially in Asian countries. Since the majority of human cases reported in Thailand were infected by the consumption of a raw pork dish, the microbial food safety hazard associated with raw meat has been a matter of concern. Therefore, this study aimed to investigate the contamination by S. suis in pork and edible pig organs sold in central Thailand. Materials and Methods: In total, 88 raw pork and pig organ samples were purchased from markets, butcher shops, and supermarkets in central Thailand. The samples were examined using the loop-mediated isothermal amplification (LAMP) technique. LAMP reactions used for the detection of the DNA of S. suis (LAMPSS) and S. suis serotype 2 or 1/2 (LAMPSS2) were carried out according to previous studies. Results: The percentage of LAMPSS-positive samples was as high as 85.23% (75/88) while the percentage of LAMPSS2- positive samples was 17.05% (15/88). The percentages of LAMPSS- and LAMPSS2-positive samples were relatively high in both pig organs (lung and heart) and meat (sliced pork and minced pork) compared with the previous report. Except one supermarket, LAMPSS-positive samples were found in all sources investigated in this study. The pork and pig organs obtained from the markets and the butcher shops additionally gave positive results for LAMPSS2. Conclusion: Using LAMP techniques, high rate contamination of S. suis was found in raw pork and edible pig organs sold at different sources in central Thailand. The cross-contamination could have occurred through slaughtering, meat cutting, and meat handling processes. Therefore, consumers and people involved in the pig production industry should be aware of the potential hazards of S. suis infection; food safety education is crucial to prevent further infection.

Methicillin-resistant staphylococci (MRS) have been considered a veterinary and public health threat that needs to be addressed, as they are known to cause serious infections, with limited therapeutic options. Thus, in this study, we aimed to examine the potential antibacterial activity of the leaf extract of Solanum torvum against MRS isolated from clinically healthy dogs. In total, seven mecA-positive Staphylococcus isolates tested in this study were identified using 16S rRNA gene sequencing, and all of them were classified as multidrug-resistant using disk diffusion tests. According to gas chromatography-mass spectrometry analysis, the main phytochemical components found in the leaf extract were hexadecanoic acid and its ethyl ester and 9,12,15-octadecatrienoic acid, ethyl ester, (Z,Z,Z). The minimum inhibitory concentration (MIC) breakpoints for the leaf extract against all tested isolates ranged from 2 to 16 mg/mL, while the MIC breakpoints for oxacillin were from 2 to 512 mg/L. Although varying effects were found, the positive effects of the leaf extract were most evident in combination with oxacillin. These results suggested that S. torvum leaf extract may complement classical antibiotics and may potentially drive the development of an effective therapeutic option for MRS.

Background and Aim: Trichuris trichiura and Hymenolepis diminuta are helminthic intestinal parasites that infect humans and other animals, including non-human primates. However, molecular detection of these parasites remains scarce in long-tailed macaques (Macaca fascicularis), which coexist with human communities in Thailand. Thus, this study aimed to molecularly confirm the occurrence of Trichuris spp. and Hymenolepis spp. infection and determine the species of both parasites that were found in long-tailed macaques. Materials and Methods: A total of 200 fecal samples were randomly collected from long-tailed macaques living in Lopburi, Thailand, and tested based on polymerase chain reaction (PCR) assays for Trichuris spp. and Hymenolepis spp. infections. The PCR products were submitted for DNA purification and sequencing. Phylogenetic analysis was performed using the maximum likelihood method. Results: Of 200 tested samples, three (1.5%) were positive for Trichuris spp. Sequence analysis of all positive samples revealed the presence of T. trichiura, while eight samples (8/200, 4%) positive for Hymenolepis spp. were classified as H. diminuta. No significant associations were found between parasite infection and sex of macaques. Conclusion: This study revealed that long-tailed macaques harbor T. trichiura and H. diminuta. These results suggested that local residents and tourists must pay attention to limiting contact with long-tailed macaques and take hygienic precautions to reduce the risk of zoonotic and anthroponotic transmission of these parasites between humans and long-tailed macaques.

Background and Aim: Toxoplasma gondii is recognized as a zoonosis causing toxoplasmosis in animals globally. Cat is a definitive host of T. gondii and sheds oocyst through feces, which can infect human beings and animals through contaminated food ingestion. A precise diagnostic test is essential to prevent T. gondii infection in both humans and animals. This study aimed to develop and evaluate the pETite- dense granule antigen 7(GRA7)-based indirect enzyme-linked immunosorbent assay (ELISA) to detect T. gondii infection in cats. Materials and Methods: T. gondii-GRA7 was cloned and expressed in the Expresso® small ubiquitin-related modifier (SUMO) T7 Cloning and Expression System. The recombinant pETite-GRA7 was purified using HisTrap affinity chromatography and confirmed using Western blot analysis. The recombinant protein was used to develop and evaluate the indirect ELISA for T. gondii infection detection. In total, 200 cat sera were tested using pETite-GRA7-based indirect ELISA and indirect fluorescent antibody test (IFAT). The statistical analysis based on Kappa value, sensitivity, specificity, positive predictive value, negative predictive value, χ2 test, and receiver operating characteristic (ROC) curve was used to evaluate the performance of the test. Results: A 606 bp GRA7 polymerase chain reaction (PCR) product was obtained from T. gondii RH strain genomic DNA. The gene was cloned into the pETite™ vector and transformed to HI-Control Escherichia coli BL21 (DE3) for protein expression. Approximately 35 kDa of recombinant pETite-GRA7 was observed and Western blot analysis showed positive bands against anti-6-His antibody and positive-T. gondii cat serum. A sample of 0.5 μg/mL of pETite-GRA7 was subjected to indirect ELISA to detect T. gondii infection in the cat sera. The results showed sensitivity and specificity of pETite- GRA7-based indirect ELISA at 72% and 96%, respectively. An acceptable diagnostic performance was characterized by high concordant results (94%) and substantial agreement (Kappa value=0.65) with IFAT. The seroprevalence levels of ELISA and IFAT were 10% and 9%, respectively, and were not significantly (p>0.05) different. The expected performance of ELISA at different cutoff points using the ROC curve analysis revealed 89% sensitivity and 92% specificity at the cutoff value of 0.146, with a high overall assay accuracy (area under the curve=0.94). Conclusion: In this study, the pETite™ vector, N-terminal 6xHis SUMO fusion tag, was used to improve the solubility and expression level of GRA7. The recombinant pETite-GRA7 showed enhanced protein solubility and purification without special condition requirements. This pETite-GRA7-based indirect ELISA showed high concordant results and substantial agreement with IFAT. ELISA revealed an acceptable sensitivity and specificity. These initial data obtained from cats' sera demonstrated that pETite-GRA7-based indirect ELISA could be a useful method for local serological diagnosis of T. gondii infection in cats in Thailand.